Analog Devices VISUALDSP++ 3.5 Manual page 246

Smaller Applications: Optimizing for Code Size
quently executed regions of code for maximum performance, while
keeping the infrequently executed parts as small as possible. The switch is
most reliable when using profile-guided optimization, since the execution
counts of the various code regions have been measured experimentally.
Without PGO, the execution counts are estimated, based on the depth of
loop nesting.
Tip: Avoid the use of inline code.
Avoid using the
a number of times, especially if they not very small functions. The
switch does not have any effect on the use of the
however, prevent automatic inlining (using the
ing the code size. Macro functions can also cause code expansion and
should be used with care.
2-30
keyword to inline code for functions that are used
inline
VisualDSP++ 3.5 C/C++ Compiler and Library Manual
keyword. It does,
inline
switch) from increas-
-Oa
for ADSP-219x DSPs
-Os